This invention relates generally to sealing means and, more particularly, to a device for providing a water seal between a stationary and a vibrating body.
In the field of atmospheric pollution control, it is known to use an adsorptive process for the desulfurization of flue gas in which the sulfur-containing material is adsorbed in the porous system of a carbonaceous adsorbent material. The saturated adsorbent material, which is a material called char and is commonly in pellet form, is regenerated by a process in which the sulfur-containing material is chemically changed in form, such as the decomposition of sulfuric acid to sulfur dioxide, carbon dioxide and water. The regeneration of the saturated char can be accomplished by washing (wet regeneration) or by contacting it with hot sand (thermal regeneration). Wet regeneration produces dilute sulfuric acid (18% by weight) as a by-product, and because of the limited use for this by-product, thermal regeneration is the more practical method.
In thermal regeneration, an enclosed, refractory-lined vessel is normally utilized to contact the saturated char pellets with hot sand, which has been heated to a predetermined elevated temperature to act as an inert heat-transfer media. As the char pellets become heated, the reactions that occurred during the adsorption process are reversed, producing a concentrated stream of sulfur dioxide, water, carbon dioxide, and nitrogen.
In these type arrangements the mixture of hot sand and char flows slowly down through the regeneration vessel, with the flow being controlled by a char-sand separator/feeder positioned below the discharge hopper of the vessel. The char-sand separator/feeder not only controls the flow rate of the materials through the regeneration vessel, but also acts to separate these two materials after regeneration has taken place. The char pellets are separated, subsequently cooled, and returned to the adsorber for reuse, and the sand passes through a screen in the separator/feeder and is returned to a sand heater, which restores the heat lost to the char during the regeneration process and recycles the reheated sand to the top of the regeneration vessel.
Separation of the two materials is effected by vibration of the separator/feeder. The regeneration vessel, of course, is stationarily supported, and the by-products of the regeneration process are gaseous. Thus, it is essential that an effective, gas-tight seal be provided between the discharge hopper of the stationary regeneration vessel and the vibratory separator/feeder. This particular environment presents a set of unique problems since a suitable sealing device must be gas-tight, withstand high temperatures and vibrations, and be resistant to the abrasive effects of the sand-char mixture flowing from the hopper. Further, pressure differences exist between the regeneration vessel and the separator/feeder, which must be adequately accommodated by the sealing device.
Mechanical-type sealing devices, such as gaskets, flexible couplings, bellows, and the like, which may be made of metallic and/or elastomeric materials, are not totally satisfactory, since they do not provide all of the aforesaid desirable characteristics necessary for an effective, durable seal between the regeneration vessel and the vibratory separator/feeder.